Apparatus for rapid reduction of iron oxide in a rotary hearth furnace

Abstract

A method and apparatus for producing direct reduced iron from dry compacts composed of iron oxide and carbonaceous material by feeding compacts no more than two layers deep onto a hearth and removing all the volatiles and metallizing the compacts by exposing said compacts to a radiant heat source at a temperature of from about 2400° to about 2600° F. (1316°-1427° C.) for a total time period of about four to ten minutes and partially cooling the compacts while discharging them from the hearth.

What is claimed is: 
     
       1. Apparatus for producing metal from direct reduced iron from dry compacts of iron oxide and particulate carbonaceous material in a rotary hearth furnace, comprising: a. means for mixing iron oxide fines and particulate carbonaceous material and forming dry compacts;   b. a rotary hearth furnace having a generally flat hearth surface for receiving the dry compacts;   c. means for feeding the dry compacts in no more than two layers on the surface of said hearth;   d. means for heating, reducing, and sintering said dry compacts on said hearth to form a reduced product;   e. means for infecting a coolant in the vicinity of said compacts;   f. means for discharging said reduced compacts from said rotary hearth furnace; and   g. means intermediate said feeding means and said discharge means for removing flue gas from said rotary hearth furnace.   
     
     
       2. Apparatus according to claim 1, further comprising means for partially cooling the compacts while discharging them from the hearth. 
     
     
       3. Apparatus according to claim 1, wherein said means for feeding said compacts one to two layers deep onto the hearth comprises at least one vertical feed pipe having an adjustable gate, or leveler, having a lower edge to control the thickness of the layer. 
     
     
       4. Apparatus according to claim 1, wherein said means for discharging of compacts from the hearth comprises at least one helical screw. 
     
     
       5. Apparatus according to claim 1, wherein said means for discharging of compacts from the hearth comprises at least one plow. 
     
     
       6. Apparatus according to claim 1, further comprising a water-cooled probe for collecting a gas sample less than one inch above the surface of said compacts immediately prior to their discharge from said hearth, whereby the levels of carbon monoxide and oxygen in said gas sample are monitored for purposes of product quality control and/or optimization of productivity.